Effects of serum on calcium mobilization in the submandibular cell line A253

✍ Scribed by Xiuhua Sun; Ann-Christin Mörk; R.J. Helmke; J. Ricardo Martinez; Guo H. Zhang

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 169 KB
• Volume: 73
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/(sici)1097-4644(19990615)73:4<458::aid-jcb4>3.0.co;2-0

✦ Synopsis

The effects of serum on inositol 1,4,5-trisphosphate (IP 3 ) formation and Ca 2ϩ mobilization in the human submandibular cell line A253 were studied. Exposure of A253 cells to fetal bovine serum (FBS) elicited a 3.3-fold increase in IP 3 formation and a concentration-dependent transient increase in cytosolic free Ca 2ϩ concentration ([Ca 2ϩ ] i ), which was similar in Ca 2ϩ -containing and Ca 2ϩ -free media. Newborn bovine serum (NBS), but not bovine serum albumin (BSA), induced a similar response. The Ca 2ϩ release triggered by FBS was significantly (88%) reduced by the phospholipase C inhibitor U73122, indicating that Ca 2ϩ release induced by FBS is through the PLC pathway. Pretreatment with the tyrosine kinase inhibitor genistein abolished the FBS-and NBS-induced Ca 2ϩ release, suggesting that tyrosine kinase plays an important role in mediating the Ca 2ϩ release. Pre-exposure to ATP or thapsigargin (TG) significantly reduced the FBS-induced [Ca 2ϩ ] i increase, indicating that Ca 2ϩ release caused by FBS is from the TG-or ATP-sensitive Ca 2ϩ store. While FBS exposure elicited a large Ca 2ϩ release, it reduced Ca 2ϩ influx. Furthermore, FBS significantly inhibited the Ca 2ϩ influx activated by the depletion of intracellular stores by ATP or TG. These results suggest that (1) serum elicits Ca 2ϩ release from ATP-and TG-sensitive stores, which is mediated by IP 3 ; (2) the serum-induced Ca 2ϩ release may be modulated by a tyrosine kinase-associated process; and (3) serum strongly inhibits Ca 2ϩ influxes including the store depletion-activated Ca 2ϩ influx.